井下管串壓差卡鉆黏附阻力計算模型

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CalculationModelforAdhesionResistanceinDifferential Pressure Sticking of Downhole String

Zhou Yuting1Zhang Hui1Yang Boyuan1Wang Peng1.2.3Yu Qing4Liu Kerou1Lu Kunhong1 （1.ColegeofPetrolemEngneeing，China Uniersityofetrole（Beiing）;2.CNCEngineingTeoogyR&DCni ited;3.NationalEngineeingResechenteofOil&GasDrilingandCompletionTecolog；4JinghanMacnryReeaIst tute Limited Company of CNPC）

Abstract： Diffrential pressure sticking is one of the main causes for significantly increased non-production time and cost.The existing research on diferential presure sticking often relies onempirical summaries offield data or laboratory tests，while the current theoretical model research also fails to consider the stress on pipe string， wellboreconditionand mudcake strength.In this paper，considering the length，force and area of contact between the pipe string and the wellore wall，a calculation model for theadhesion resistance in diferential pressure stickingofdownhole string was built.Then，the model was used forsensitivityanalysis ontheaxialforceofthe string，the wellbore parameters（welldiameter，hole angle，dogleg）and the mud cake parameters（mud cake thickness，elastic modulus，Poisson'sratio，permeability），to understand how these factors affecttheadhesion resistane.Finally，the model was verified through exampleapplication.Theresults show that fortheaxial force of the string，theadhesion resistancedecreases withthe increase of tensionand increases with the increase of pressure.Forthe main wellbore parameters，the adhesion resistance decreases with the increase of welldiameterand increases with the increase of holeangleanddogleg.For the main mud cakeparameters，theadhesion resistance decreases with the increase of the elastic modulusof the mud cake，slightlydecreases with the increase ofthe Poisson’sratio of the mud cake， and first increases and then tends tobe smooth with the increase of the mud cake permeability；and the maximum adhesion resistance increases with the increase of the mud cake thickness.The research results provide a theoretical basis forthefurtherresearchondiferential pressure sticking andatheoretical guidanceforthefield pre-vention of sticking accidents.

Keywords：downhole string;diferential pressure sticking；adhesion resistance；frictional torque；axial force： wellbore pa-rameter；contact mechanics

0 引言

壓差卡鉆是顯著延長非生產(chǎn)時間、增加成本的主要原因之一[1]。（剩余12239字）